A very interesting study appearing last week in the journal “Science” relied on a test from the Programme for International Student Assessment (PISA). It assessed over 275,000 15 year old teenagers in 40 countries. One of the most fascinating conclusions of this study was that, despite the usual reported gap in math and reading scores between boys and girls, the explanation for such a discrepancy could perhaps lie not in biology but instead could have more to do with gender equality. John Timmer from Ars Technica reports:

The researchers, noted, however, that the math gap wasn’t consistent between countries. For example, it was nearly twice as large as the average in Turkey, while Icelandic girls outscored males by roughly 2 percent. The general pattern of these differences suggested to the authors that the performance differences correlated with the status of women. The authors of the study built a composite score that reflected the gender equality of the countries based on the World Economic Forum’s Gender Gap Index, data extracted from the World Values Surveys, measures of female political participation, and measures of the economic significance of females.

Scandinavian countries such as Norway and Sweden score very high on gender equality measures; in these nations, the gender gap on math performance is extremely small. In contrast, nations at the other end of the spectrum, such as Turkey and Korea, had the largest gender gap. The correlations between gender equality and math scores held up under a statistical test designed to catch spurious associations. The authors even checked out the possibility of genetic effects not linked to the Y chromosome by examining whether genetic similarity between various European populations could account for these differences, but they found that it could not.

The frightening thing, from a male perspective, is that a lack of gender equality also seems to be holding down girls’ reading scores. Female superiority in reading tests is slightly lower than average in Turkey, but the gap is actually wider in countries with greater equality between the sexes. In Iceland, for example, girls outscore boys by well over 10 percent.

The math gender gap thus joins a long list of differences in test scores that were once ascribed to biology, but now appear to be caused by social influences. The study, however, leaves us with yet another question of this sort: why do boys appear to read so poorly? We clearly can’t ascribe it to social inequality, but that doesn’t mean it isn’t due to some other social factor.